Comments on the sinking of the MV Sewol 16 April 2014, Part 2: Evacuation issues associated with the Sewol incident — written by Prof Ed Galea, 20 April 2014 20:00

As in most disasters of this type, so soon after the incident, information concerning the nature of this incident is far too sketchy to draw any firm conclusions. Indeed, at the time of writing there are more questions than answers. In previous blogs related to ship evacuation, I have described the general ship evacuation process and implications for passenger ship safety; I will not repeat these here, but suggest that interested readers should refer to my earlier blogs on the Costa Cordia:

In my previous blog I reported what we currently know about the Sewol disaster, based on current media accounts. Here I will explore to explore the ship evacuation process, what hampered the evacuation of the passengers on the Sewol and some of the implications for passenger ship safety.

The latest reports from South Korea now suggest that of the 476 people on board the Sewol, 174 were rescued, 54 bodies have been recovered and 248 people are still missing.

The sinking of the Sewol bears a striking resemblance to the Costa Concordia incident. Many factors strongly influential to evacuation outcomes were common to both cases. Some of these should have assisted the passengers, while others undoubtedly impeded their safe evacuation. The common factors that should have contributed to a favourable evacuation include:

1) The incidents occurred under the jurisdiction of modern well-developed countries

This should have helped, but it does not mean that the shipping companies involved have a well-developed safety culture, or the regulatory and inspection facilities in each country are well developed and appropriate.

2) The vessels were relatively modern

The Costa Concordia was launched in 2005, and the Sewol in 1994. As both are relatively modern vessels they would have benefited from modern design practices and knowledge of safety issues. However, the Sewol was completed in the year of the Estonia disaster. This disaster lead to a number of significant changes to IMO regulations for Ro-Ro ferries such as the Sewol, but they came too late to impact the design of the Sewol.

3) The weather was calm

Bad weather can complicate the evacuation process, making it difficult to safely evacuate a large passenger vessel; however, in both cases, the sea was calm, and the conditions were not harsh. While the water temperature in the case of the Sewol incident was cool, it is unlikely that the passengers would have remained in the water for a dangerously long period of time, especially given (4), (5) and (6).

4) The vessels were on well-known routes and in busy shipping lanes

If the ship is in unfamiliar waters with little traffic it may complicate the decision to evacuate the vessel as the survivors may have to spend a long time in the water in lifeboats. However, this was not the case in either of these incidents.

5) The vessels were close to land

The fact the vessels were close to land meant that help was not far away.

6) The vessels were in radio contact with the coast guard at the time of the incident

The fact that the vessels were in contact with the coast guard from the start of the incident meant that help was be quick in arriving.

7) The vessels were not overcrowded and there were sufficient lifeboats for the population

In the case of the Sewol, the vessel was carrying significantly less than the maximum capacity of the vessel. In both cases, there was ample capacity in the available life boats.

8) The captains were experienced master mariners

Both captains had considerable experience and should have been expert in the handling of their vessels, and the dangers associated with taking on water, particularly, in the case of the Sewol, of taking on water on the car deck. Both should also have had a good working knowledge of the evacuation process and the need for speed.

Items (1) to (8) meant that the in both cases, these disasters occurred under somewhat ideal conditions and so we should have expected a much better outcome. Indeed, both cases should have been more survivable, had the evacuation been managed in a more efficient and timely manner.

In both cases the factors that contributed to the disastrous outcome of these evacuations include:

9) The passengers were not required to complete an assembly drill to familiarise themselves with the evacuation process prior to departure

In the case of the Costa Concordia an evacuation drill was not required prior to departure, but within 24 hours of departure. In the case of the Sewol, as the journey was less than 24 hours an evacuation drill was not required at all. This meant that it was unlikely that the passengers were familiar with the evacuation procedures.

10) Both Captains failed to start the assembly process within a reasonable period of time

This meant that the passengers were not in a position from where they could rapidly and easily abandon the vessel or be easily rescued by emergency responders, should this prove to be necessary.

11) Counter intuitive instructions were given to the passengers

Not only were passengers not given the command to assemble, they were effectively given instructions NOT TO assemble. In the case of the Sewol, it is reported that the passengers were instructed to stay where they were, while in the case of the Costa Concordia, passengers were told that there was not a serious problem and that they should go to their cabins.

12) Both vessels capsized but this took more than 30 minutes

In both cases, there would have been sufficient time for most, if not all of the passengers to get to their assembly stations from where they could abandon the ship, had the assembly process started sufficiently early.

13) Failure to launch sufficient lifeboats (or liferafts)

Delay in starting the evacuation process meant that it was impossible to launch sufficient lifeboats in the case of the Costa Concordia, or virtually any liferafts in the case of the Sewol. Davet launched lifeboats cannot be launched when the angle of heel exceeds 20O and the liferafts cannot be launched if the crew cannot reach them due to adverse angles of heel.

14) Both captains abandoned the vessel before their passengers and crew had safely evacuated.

In both cases it is reported that the Captain did not remain on board to manage the evacuation of the people in their care. Essentially they left the passengers to fend for themselves.

Failure to start the assembly process as soon as possible contributed to the disastrous outcome in both cases.

Why is it so important to start the assembly stage as early as possible?

In an evacuation situation, every second counts and seconds can mean the difference between life and death. On board a large passenger ship, the evacuation process is usually undertaken in two parts: the assembly phase, and the abandonment phase. This is explained in more detail in an earlier blog concerning the Costa Concordia (http://fseg.gre.ac.uk/blog/?p=110).

During the assembly phase, passengers are instructed to go to their assembly stations. Passengers will be given lifejackets at the assembly stations, or they will bring their lifejackets from their cabins. Assembly stations are close to the points from which passengers can embark onto the lifeboats if the captain decides to go to the second phase of the evacuation, the abandon ship phase. It is vitally important that the assembly phase is completed as quickly as possible because conditions on board may make it impossible for passengers to get to a place from where they can abandon the vessel, if conditions deteriorate, such as if there is a fire on board, or if the vessel is heeling over, as in the case of the Costa Concordia and the Sewol. If passengers are in the assembly stations it will also be easier for emergency teams to rescue the passengers compared to if they are located deep within the vessel.

Imagine you are in your cabin and you need to get to the assembly station. Let’s assume that the assembly station is on your deck so you don’t have to climb or descend any stairs. You will have to get out of your cabin, pass along a corridor running along the length of the vessel and then eventually pass through a corridor running across the vessel linking the left with the right part of the vessel.

When the vessel is upright, this is a relatively easy thing to do and you can pass from left to right or from right to left easily, depending on which side you need to move to (see Figure 1). If the vessel takes on a slight heel, say less than 5O, movement is still relatively easy, assuming that you are not elderly or disabled (see Figure 2); however at 20O of heel, it starts to become very difficult to move up the slope and to control your movement going down the slope (see Figure 3). Your travel speed up and down the slope is greatly reduced, resulting in it taking considerably longer to assemble the passengers. If you have elderly or disabled passengers, it is unlikely that they will be able to move unaided.

Angles of heel from 0 degrees to 20 degrees

When the angle of heel reaches 45O, it is extremely difficult to move up the slope without travelling at a crawling pace, and you will need to hold onto things such as handrails to progress (see Figure 4). Going down the slope in a controlled manner also becomes very difficult. If you are elderly or disabled, it is unlikely that you will be able to move, even with assistance.

At 60O of heel, it is unlikely anyone will be able to move up the slope, and the only way is down or staying where you are (see Figure 5). If the passengers have not reached the assembly stations by the time the angle of heel has reached 60O, it is unlikely that they are going to be able to move across the vessel against the slope.

Angles of heel from 45 degrees to 60 degrees

If passengers are still in their cabins when the heel is much greater than 20O, it is unlikely that they will be able to get out of their cabins, let alone make it to their assembly station. Imagine now that if you had to ascend or descend stairs to reach your assembly station, how much more difficult it would be, compared with simply walking along a corridor! Even walking along the long corridors running the length of the vessel becomes difficult when the ship takes on an angle of heel greater than 20O. The passenger is pulled down to the low side of the corridor and has to walk partially on the floor and partially on the bottom of the wall. Here again the speed at which the passenger can move is greatly reduced AND the effective width of the corridor is greatly reduced, making it more difficult for crowds to move along the corridor.

This is why it is essential that passengers must complete the assembly process and locate themselves in a place from which they can abandon the vessel easily or be easily rescued if necessary. So it is essential that the assembly phase of the evacuation is started as soon as possible. Assembling the passengers does not necessarily mean that they will have to abandon the vessel, but if they need to do so, they will at least be able to. I find it hard to understand why a captain of a vessel that is in distress – so much so that they have alerted the coast guard – would not have started the assembly process, if for no other reason than as a precaution. In my earlier blog concerning the Costa Concordia (http://fseg.gre.ac.uk/blog/?p=126) I offer some suggestions as why this may happen. But it may also simply be down to denial. The captain and senior officers may simply be denying the seriousness of the situation, believing that they can remedy it, and there is no need to evacuate. If so, this becomes a training issue and one concerned with safety culture, both on board the vessel and also in the operating company that runs the vessel.

Did social culture play a role in the outcome of the Sewol disaster?

It has been suggested that social culture of the South Korean people had a role to play in the outcome of the Sewol evacuation. In particular, the suggestion is that South Korean culture demands that people are respectful of authority and are compliant with the wishes of those in authority. Had the passengers been from a different cultural group they may have reacted differently to the order to stay where they were.

Recent work by my research team as part of an EU FP7-funded project BeSeCu [1,2,3] suggests that social culture may influence the way in which people respond to alarms. It was noted in this research that when faced with virtually identical situations, groups of people from one culture tended to react significantly more rapidly than groups from other cultures when faced with a fire alarm. This is further discussed in a paper we published recently with the Royal Institution of Naval Architects, concerning evacuation from large passenger ships [4], as part of the EU FP7 SAFEGUARD project [5].

However, I am not convinced that simply responding to an instruction from an authority figure is a cultural trait unique to the South Korean people. Our research into the World Trade Center evacuation [6] suggested that when people in the South Tower of the WTC heard the instructions over the PA system that they should return to their offices, as they were safe in the South Tower, (as only the North Tower had been hit at this time), many did so – and died [7]. Also, many passengers on the Costa Concordia also complied with the instructions of the crew, at least initially.

Perhaps it is more relevant that the majority of people on board the Sewol were children and so more likely to follow the commands of an authority figure. This is probably likely to be the case in most cultures. Furthermore, as with the Costa Concordia disaster, safety culture (or the lack of a healthy safety culture), as opposed to social culture, may have played a more important role in this disaster.

Assembly drill requirements

As has already been stated, according to IMO regulations, it is not compulsory to have an assembly drill prior to the departure of the vessel for voyages of less than 24 hours; however, as the Sewol and Costa Concordia incidents have tragically demonstrated, fatal accidents requiring the abandonment of the vessel can occur at any point of a voyage, even as little as a few hours after departure. In both cases, the passengers would have benefited from having experienced the assembly process prior to the fatal accident.

The point of the assembly drill is twofold: firstly, and most importantly, to familiarise passengers with the assembly procedures and the location of the assembly stations; secondly, to provide the crew with training in the management of large crowds of passengers. The need to undertake the assembly drill becomes more critical the larger the number of passengers on board, and the more complex the layout of the vessel. Indeed, the duration of the voyage is somewhat irrelevant when setting a lower limit for the need to undertake an assembly drill.

The difficulty for a regulatory body is in defining critical limits on duration of voyage, population size and complexity of vessel layout that are meaningful and not arbitrary; nevertheless, in addition to the current voyage duration criterion, sensible limits could be placed on the other factors. Addressing complexity, if a significant number of the passenger population is accommodated within cabins, the layout of the vessel will be more complex than a vessel not having cabins. Thus if a significant number of passengers are accommodated within cabins, the complexity criteria will require an assembly drill. In terms of the size of the passenger population, if the predicted assembly time for the vessel is within 20% of the maximum allowed assembly time, then the population criteria will be met to require an assembly drill.

So rather than having a single factor (duration of voyage) determining whether or not an assembly drill is required prior to departure, three factors addressing different challenging evacuation issues should be considered:

Duration of voyage: if the voyage is greater than 24 hours, an assembly drill must be undertaken. This ensures that the current criterion is maintained. The longer the voyage the greater the chance that an accident may occur and, hence, that an assembly may be required.

Complexity of vessel: if more than 30% of the passengers on the voyage are to be accommodated within cabins, then an assembly drill must be undertaken. This ensures that passengers travelling on vessels with complex layouts will undergo an assembly drill prior to departure.

Number of passengers: if the predicted assembly time for the vessel is within 20% of the maximum allowed assembly time, an assembly drill must be undertaken. This ensures that vessels with large numbers of passengers for their size will have an assembly drill prior to departure.